1. Field of the Invention.
The present invention relates to the art of restoring and conserving oil paintings on canvas, and particularly to the art of integrating a restored painting with a suitable backing.
2. Description of the Related Art.
Oil paintings on canvas have only a limited time period before they start to disintegrate. Although the paint film may endure for centuries, the canvas undergoes continuous and fairly rapid chemical and physical decomposition. Consequently, restoration is often required within decades.
Conventionally, painting restorers laminate a new canvas backing over the deteriorated canvas in a process called lining. After a period of time, the second canvas deteriorates and must be replaced (relining). This repeated process dictates the use of a reversible adhesive, since the previously laminated canvas backing must be removed before applying a new canvas backing. Restorers traditionally use hot melt adhesives for the lining and relining processes, for these adhesives lend themselves to easy removal. Historically, beeswax has been the hot melt adhesive used, but in recent years some restorers have tried synthetic hot melt adhesives. Because it is recognized that heating can damage the paint film, some restoration has been performed using pressure sensitive adhesives at normal room temperatures.
Instead of canvas, it has been proposed in U.S. Pat. No. 4,330,586 of FIEUX to use a flexible substrate layer of fine mesh synthetic material, such as a woven polyester monofilament, fiberglass, or a polyester mylar. The substrate may be fixed to the rear face of the original canvas of an oil painting by a silicone pressure sensitive transfer adhesive applied at room temperature. Alternatively, FIEUX suggests a heat activated adhesive, such as ethylene vinyl acetate or a wax resin. The substrate can be used alone, or it can be backed with a canvas or poplin lining.
It is well recognized that any work done on a painting damages it. The lining and relining processes expose the painting to physical and chemical damages. Hot melt adhesives thermally damage the paint film, both when applied and when subsequently removed. Adhesives that require solvents for removal inflict chemical damage to the paint film. Water based adhesives cause the canvas to contract and expand, thus stressing the paint film.
The deterioration of the original canvas is the most damaging of all to the paint film. As the canvas decomposes, it loses its original function, that of supporting the paint film. This causes the film to crack and ultimately to separate from the canvas. Contractions and dimensional changes in the original canvas introduce stresses in the paint film that further weaken it. The application of a second canvas backing and filling of voids with adhesives or waxes does not alleviate the stresses induced by the dimensional changes in the original canvas. The added lining simply provides a temporary treatment to the painting. As long as the original canvas is intact, it will continue to deteriorate and the paint film will continue to lose its support. The deteriorated canvas will continue to stress the paint film. Over time, many works of art are lost long before the paint film deteriorates, due to the instability of the canvas. Even the use of synthetic materials for lining and relining does not appreciably help the situation, since the deterioration of the original canvas continues to introduce stresses in the paint film.